Control means for helicopters



' Jall- 7- R. R. HAYs ETAL 2,414,258

CONTROL MEANS FOR HELICOPTERS Filed Oct. 8, 1943 5 Sheets-Shet 1 ?(/556// R Hays, Char/c5 A. fiazaK,

Jan. 14, 1947. R. R. HAYS E' I'AL 2,414,258

- QNTROL MEANS FOR HELICOPTERS Filed Oct 8 1945 5 Sheets-Sheet 2 Jan. 14, 1947. R..R. HAYS ETAL I CONTROLMEANS FOR HELICOPTERS Filed Oct. 8, 1943 SSheets-Shget 3 FUJscV/7RT-Z yhar/es 15 4206:

Patented Jan. 14, 1947 CONTROL MEAN FOR HELICOPTERS Russell R. Hays, Lawrence, and Charles Kenneth Razak, Wichita, Kane; said Bazak assignor to said Hays Application October 8, 1943, Serial No. 505,526

13 Claims.

This invention relates *to control means for helicopters and more particularly to improvements in tension panel controls such as those described in co-pendinq application Serial No. 491,977, filed June 23, 1943, by Russell R/Hays, one of the present applicants.

Tests of control panels operative in the slipstream of a lifting propeller revealed that devices such as drag flaps, when mounted on opposite panels and differentially operated to provide a rolling moment, had the effect of decreasing the sensitivity of the same panels when utilized to produce pitching moments and hence introduced confusion in the degree of operation of the control column. This led to the testing of panel arrangements symmetrically disposed about the rotor axis and rigged to a conventional control stick so that movement in a desired direction varied the pitch of panels transverse to this direction and thus produced a control moment of the same order as sectional feathering controls now used on several fullscale machines. Further investigation revealed however that conventional arrangements of similar panels such as those having radial spacings of 60, 90, 120, and 180 were not in themselves directionally stable with transition to translational flight. While it was of course obvious that by varying the relative size of the panels and arranging them with different radial spacings, this handicap could in part be circumvented, it was equally obvious that simplicity of operation during hovering flight to provide the equivalent of a sectional control was thereby lost.

The value of tension panels in making the transition from hovering to translational flight having already been determined, a detailedstudy was made of the adaptation of similar, symmetrically disposed panels to obtain inherent directional stability during translational flight. That three such panels were the minimum which could be used to provide a complete sectional control during hovering was of course self evident. The problem thus became one of developing a mounting and control means for such an arrangement which with translation would automatically change the character of such a symmetrical disposition of similar parts that they would assume directional stability characteristics substantially those of the tail plane.

In the beginning, an effort was made to add to the span of two of the panels so that the tips,

being outside the slipstream of the propellers during hovering, would ward speeds were achieved. This, at empted not be effective until for-'- solution, however, added considerable structure and did nothing to simplify the control since a dual control carried inside the elongated panels was now called for. Wing tip rudders also failed to supply a solution to the problem.

Real progress was'not made until it was observed that with the three panel arrangement, using self aligning 'or floating panels, a definite sluggishness to rotational movement developed when, contrary to previous conceptions, one panel was aligned rearwardly with the airstream. Investigation revealed that this sluggishness derived from two sources: one, the two panels athwart the airstream, being free to align themselves with it, had the direction of action of the lift effective upon them shifted from a direction approaching the horizontal to a direction approaching the vertical, Whereas the dominant forces effective upon the trailing panel continued to act largely in a horizontal direction; and two,

tageous for a control of thistype. These and otherconsiderations eventually led to the mounting of the panels on stub spars or shafts, whose axes are diagonal or oblique to the panel span' axes, (the term span axis is to be understood as substantially the locus of aerodynamic centers of the panel sections) with the centers of pressures of the panels slightly below or rearwardly of the shafts during translational flight. Such a mounting is particularlyadvantageous in that it acts to shift the tips of the panels rearwardly with forward travel and at the same time provides a substantial symmetrically disposed mounting for the'panels which is required only to extend outward from the mast for less than half the span of the panels.

Accordingly, the object-of, this invention may thus be broadly stated to be the provision of symmetrically disposed control panels in the slipstream of lifting propellers which become direc tionally stable by .re'asonof alignment,of the intranslation.

dividual panels With'lthe airstream resultant to of the lifting propel- A further object of the invention is the provision of floating control panels s mounted on stub spars the axes of which lie diagonally or trol panels, this control extending to a conventional universally mounted control column so that movement of the stick in any direction actuates the panels to provide a control moment in the same direction.

Yet another object is the provision of a tension panel control for lifting propellers in which only three similar panels are used and in which the arrangement of the panels relative .to mast of the machine is such that one of the panels lies behind the mast and is aligned with the direction of travel, whereas 'the other two panels lie athwart the direction of travel.

Ancillary objectives such as simplicity of parts and ruggednessof construction will be apparent from the following description takenwith the accompanying drawings in which:

Fig. 1 is a plan view of a helicopter provided with control panels arranged and mounted in accordance with the present invention.

Figs. 2 and 3 are front andside elevations, re spectively, of the machine and controls therefor illustrated in Fig. 1.

Fig. 4 is'a perspectiveview of the panel mounting, and which further illustrates one form of cable control for the panels, the'fuselage and mast of the machine being shown in dotted lines for clarity.

Referring now tothe drawings; reference char acter Ill represents a, more or less conventional fuselage having a vertical tail plane H extending aft, provided with laterally extending stabilizers I2. The fuselage carries a mast I53 through which extend oppositely turning concentric drive shafts (not shown) which drive the coaxial rotors l4,

l5 in opposite directions and with equal torque, as is well known.

According to the invention, three similar control panels are mounted as shown in the slipstream of the propellers, being substantially symmetrically disposed about the vertical axis of the mast l3, and arranged relative thereto :so that one of the panels (the rear panelw) lies behind the mast and is aligned with the direction of translational travel, whereas the other two panels, i. e., the right forward panel 2| and the left forward panel 22, lie athwart the direction of travel. Due to the aforesaid disposition of the 'two for- Ward panels and their mounting, to be described,

which permits them to swing back relative to the direction of travel from the broken to the full line position as seen inFig. 1, a'high degree of visibility for the pilot, whose view would otherwise be obstructed is accordingly provided.

The similar panels are of the floating type disclosed andcla med in the aforesaid Hays applicati0n, Serial No. 491.977, so-that theyarie free to align themselves with the resultant .airstream. Such floating panels arecharacterized'by a slight tendency toward rearward shifting of their centers .of pressure which lie to the rear or downwardly of the axes relative to-which the panels are. mounted for turning movement. According to the present invent on, this tendency is :in-.

creased by mounting the panels on the :axis .of

4 stub spars or shafts which extend diagonally or obliquely relative to the span axes of the panels, whereby with translation the character of the symmetrical disposition of the similar anels is changed automatically to one in which the panels provide stability characteristics substantially those of a tail plane.

Such a panel mounting is:illustrated in Figs. 1 and 4 wherein it will be observed that the axes XX of the stub shafts 25, 28 and 21, carrying the panels 29, 2| and 22, respectively, are disposed at an oblique angle Z relative to the span axes YY of the panels. With the centers of pressure of the panels being disposed below (rearwardly) of the shaft axes, it will be evident that in their aligning movement, the panel tips travel in an orbital are about the extended axes X-X, and that the tips of the front panels shift rear Wardly with forward travel of the machine. The diagonal disposition of the stub shafts relative to the span axes as aforesaid moreover provides a substantially symmetrically disposed mounting" for the panels according to which the stub shafts are required to extend outwardly of the mast l3 for less than half the span of the panels as measured in Fig. 1 for example. 7

With the rear panel 23 aligned rearwardly with the airstream and with the right and left panels.

free to align themselvesindividuallywith the airflow resultant to translation, a substantial degree of directional stability is provided duringtransh tion to forward flight due to the change of direc-- tion of the'resultant forces on the forward panels lying athwart the direction of motion as the latter swing rearwardly with forward travel .to form an asymmetrical pattern relative to rear.

panel, as seen in plan view (Fig. l).

The invention further incorporatesmeans for movingthe controlpanels to provide forsectional control through the panels, that is, a moment at any section of a disc toward which .a universally mounted control stick is moved. Such an arrangernent is more or less diagrammaticallyillustrated in Fig. 4, wherein a control stickilfi is universally mounted in a bearing '35 disposed intermediate upper and lower points of connection with cable sets extending to pulleys fast on the stub shafts on which the panels turn. One cable set for the rear panel comprises upper and lower" cables 35, 35, respectively, passing over sheaves 35a, 36a and. 35b, 35b, and being connected through multiplying bell cranks 35c, 3Bc and disaligning tension springs 35d, Mid-with a loop .31

wrapped around a pulley 38 fast on stub shaft' :2 25 mounting the rear panel 2E1. It will boundarstcod that the tension of springs 35d, 35d is calculated both to maintain the cable set under requisite tension and at the same time to permit the panel to disalign relative to the airstream in response'to movement of the stickthereby to'apply a control moment. A similar cable set, consisting of upper and lower cables 65, 46, is con-' nected to a loop il wrapped around a pulley 48- fast on stub shaft 26 panel 21.

mounting the right forward In like manner, an upper and lower cable set 55, 56 is connected to -a loop 51 wrapped q around-pulley 58 fast on stubsha-ft 27 mountingv the left forward panel. By 'theafcresaid arrangement, movement of the stick in any direction: disaligns the panels, i. e., moves-the panels about the,aXesX-X from a positionrm' which they are inalignment with the resultant airstream, thus to provide a control 'moment in stick movement.

the direction of;

Withou-tjsubstantial modification, it isalso' 56s- I:

sible tolock the forward panels in their swept back positionfor the purpose of providing stub wings acting to decrease the rate of descent in gliding flight with a dead engine. This and other variants of the use of only three control panels mounted on diagonal axes to provide directional stability during transition to forward travel are intendedto be includedwithin the scope of the invention. It is further intended that all matter contained in the above descriptionor. shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim: i 1."Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotati'on 'above the mast comprising the combination of three similar control panels, means radially mounting said panels from the mast in the slipstream of the propellers including axis structures symmetrically disposed about the mast and providing axes on which the panels are mounted for relatively free turning movement and which extend diagonally to the span axes of the panels, and means for positively turning the panels about said axes, thereby to produce control moments.

2. Control means for aircraft as set forth in claim 1, wherein the arrangement of panels relative to mast is such that one of the panels lies behind the mast and is aligned with the direction of travel and the remaining panels lie athwart the direction of travel.

3. Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotation above the mast comprising the combination of three similar control panels, means mounting said paneds in the slipstream of the propellers comprising stub shaftssymmetrically arranged about the mast and extending therefrom so as to dispose one panel behind the mast in alignment with the direction of travel and the remaining panels athwart the direction of travel, and means for differentially turning the panels about the axes of the stub shafts thereby to produce control moments.

4. Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotation above the mast comprising the combination of three similar control panels, means mounting said panels in the slipstream of the propellers comprising stub shafts symmetrically arranged about the mast and extending therefrom so as to dispose one panel behind the mast in alignment with the direction of travel and the remaining panels athwart the direction of travel, the axes of said stub shafts being diagonal to the span axes of the panels.

5. Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotation above the mast comprising the combination of three similar control panels, means mounting said panels in the slipstream of the propellers for movementindividually into alignment with the airstream resultant to translation, said means including stub shafts symmetrically arranged about the mastof the machine and extending therefrom so asito dispose one panel behind the mast in alignment with the direction of travel and the remaining-panels athwart the direction of travel, i the axes of the stub shafts being diagonal to the span axes of the panels, and the relation of said axes being such that the tips of the panels lying with forward travel, and means for positively turning said panels about'the stub shaft axes thereby to produce control moments.

6. Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotation above the mast comprising the combination of three similar control panelsdisposed in the slipstream of the propellers, of which one panel is longitudinally aligned and rearwardly disposed with respect to the direction of travel and means radially mounting said panels for turning movement about axes which are symmetrically disposed about the mast and extend diagonally to the span axes of the panels.

7. Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotation above the mast comprising the combination of three similar control panels disposed in the slipstream of the propellers, of which one panel is longitudinally aligned and rearwardly disposed with respect to the direction of travel and the two remaining panels lie athwart the direction of travel, and means radially mounting said two panels for turning movement about axes which are symmetrically disposed about the mast and extend diagonally tothe span axes of the panels, the relation of said axes being such that tips of said two panels shiftrearwardly with forward travel.

8. Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotation above the mast, comprising three similar control panels disposed in the slipstream of the propellers, of which one panel is longitudinally aligned andrearwardly disposed with respect to the direction of travel and the two remaining panels lie athwart the direction of travel, means whereby said panels may individually align themselves with the airstream, a universally mounted control member, and connections between said member and each of the panels operative upon movement of the control member in any direction to effect disalignment of the panels with the relative airstream thereby to produce a control moment in the same direction.

9. Control means for aircraft having a conventional fuselage, a mast carried thereby and sustaining propellers therefor mounted for rotation above the mast comprising three similar control panels disposed in the slipstream of the propellers, one panel being longitudinally :aligned and rearwardly disposed with respect to the direction of travel and the two remaining panels lying athwart the direction of travel, means radially mounting said panels for relatively free turning movement about axes individual thereto which are symmetrically disposed about the mast and which ar diagonal to the span axes of the panels, a universally mounted control member, and connections between said member and each of the panels operative upon movement of the member in any direction to effect movement of the panels about said diagonal axes as required to produce 7 a control moment in the same direction.

10. In a helicopter, the combination of a fuselage carrying a mast, sustaining propellers mounted for rotation above the mast, and control means comprising three similar control panels mounted in the slipstream of the propellers for turning movement about axes which are symmetrically disposed about the mast, one axis being 7 longitudinally aligned and rearwardly disposed with respect to th direction of travel, and the two remaining axes lying athwart the direction of travel, and means for effecting differential turning movement of the panels about said axes thereby to produce control moments.

11. In a' helicopter, the combination of a fuselage carrying a mast, sustaining propellers mounted for rotation above the mast, and control means comprising three similar control panels mounted in the slipstream of the propellers for turning movement aboutaxes which are symmetrically disposed about the mast, one axis being longitudinally. aligned and rearwardly disposed with respect to the direction of travel, and the two remaining axes lying athwart the direction of travel, means whereby the control panels tend to individually align themselves with their chords parallel to the relative airstream, and means for effecting differential disalignment of the panels with the relative airstream thereby to produce control moments.

12. In a helicopter, the combination of a fuselage carrying a mast, sustaining propellers mounted for rotation above the mast, and control means comprising three similar control panels mounted in the slipstream of the propellers for turning movement about axes which are symmetrically disposed about the mast, one axis being longitudinally alignedand rearwardly disposed with respect to the direction of travel, and

differential movement of the panels about their turning axes thereby to produce control moments.

13. In a helicopter, the combination of a fuselage I carrying a mast, sustaining propellers mounted for rotation above the mast, and control means comprising three similar control panels mounted in the slipstream of the propellers for turning movement about axes which are symmetrically disposed about the mast, one axis being longitudinally aligned and rearwardly disposed with respect to the direction of travel, and the two remaining axes lying athwart the direction of travel, means whereby the control panels tend to individually align themselves with their chords parallel to the relative airstream, said mounting axes being inclined to the span axes of the panels turning thereon whereby the tips of the panel lying athwart the direction of travel r shift rearwardly with forward travel, and means for effecting differential disalignment of the panels with the relative airstream thereby to. produce control moments.

RUSSELL R. HAYS. CHARLES KENNETH RAZAK. 

